An ink jet recording system can be classified into a charge control type and an on-demand type. In the charge control type, an ink conveyed to a nozzle by a pump is vibrated by an ultrasonic vibrator, and is then continuously pushed out to be very small droplets. The charge control type can thus continuously push out a quick-drying ink. In addition, over several tens of thousands of ink droplets per second which can be generated by ultrasonic vibration can be printed at high speed, which can be used as an industrial marker.
Examples of inks used for the ink jet printer include a solvent ink which is made by dissolving a resin and a dye or a pigment into a quick-drying organic solvent, and a photo-curable ink which is cross-linked by emitting UV light after recording. In particular, as compared with the solvent ink, the photo-curable ink has solvent resistance for a printing object, and has a low ink volatile content.
The ink jet printer using the photo-curable ink is described in e.g., Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2010-511529. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2010-511529 discloses the ink jet printer having a preliminary curing apparatus and a main curing apparatus emitting radiation to the downstream of the conveying path of an ink jet printing station having a print head.